I would contend that Cersei actually did the lion’s share (har har) of work in arranging Eddard Stark’s arrest, facilitated by Sansa’s revelation:

“Please, I need to speak to the queen again,” Sansa told them, as she told everyone she saw that day. Sansa IV — AGOT

“How well I know that, child,” Cersei said, her voice so kind and sweet. “Why else should you have come to me and told me of your father’s plan to send you away from us, if not for love?” “It was for love,” Sansa said in a rush. “Father wouldn’t even give me leave to say farewell.” She was the good girl, the obedient girl, but she had felt as wicked as Arya that morning, sneaking away from Septa Mordane, defying her lord father. She had never done anything so willful before, and she would never have done it then if she hadn’t loved Joffrey as much as she did. “He was going to take me back to Winterfell and marry me to some hedge knight, even though it was Joff I wanted. I told him, but he wouldn’t listen.” The king had been her last hope. The king could command Father to let her stay in King’s Landing and marry Prince Joffrey, Sansa knew he could, but the king had always frightened her. He was loud and rough-voiced and drunk as often as not, and he would probably have just sent her back to Lord Eddard, if they even let her see him. So she went to the queen instead, and poured out her heart, and Cersei had listened and thanked her sweetly … only then Ser Arys had escorted her to the high room in Maegor’s Holdfast and posted guards, and a few hours later, the fighting had begun outside. Sansa IV — AGOT

No one had given Cersei such a lovely gift since Sansa Stark had run to her to divulge Lord Eddard’s plans. Cersei VII — AFFC

A quick perusal of Cersei’s chapters doesn’t yield any quotes that suggest Baelish also went to her with information on his false partnership with Ned. (Someone else may have a quote that I’ve missed, however…?) My interpretation of the failed coup has always granted Cersei the more active role, with Baelish settling into his comfortable position as opportunist. Regardless of whether Petyr snitched (allowing for an obvious statement I’ve overlooked) or just hung back and waited to see what happened- no, Sansa is either unaware of his part in Lord Stark’s arrest or else is repressing the memory, a coping mechanism we see her use frequently in ACOK and beyond.

Although the details vary depending on who you ask, prevailing interpretation among fans holds that this will play a large part in Baelish’s downfall. Sansa knows just enough, and her intuition and critical thinking are fostered daily under his “tutelage”, that it will only take a small nudge for her to unravel his involvement in some of the misfortunes in her and her family’s past.